The main purpose of linear tomography is to blurr anything that is below or above the object plane. What this does is it increases your contrast and makes it easier to see structure that are normally blocked like the kidneys. The only disadvantage is you make a longer exposure so the patient gets more radiation dose and higher attenuation of the x-ray beam at the end.


Principle of the linear tomography it is pretty simple linear tomography uses the same principles as a normal x-ray does. What happens when you move during an exposure the object that moves gets blurred.They took that principle and added to blurring anatomy that was not important. The x-ray tube focuses on an object plane and anything below this or above it is blurred. The arrow is the only thing the x-ray tube focuses on the square and the circle are the object it wants to blurr so when the x-ray tube moves the square and the circle are moved to different areas and becomes blurred whereas the arrow is constantly in the center of the image receptor.
The equipment used in linear tomography is the same as in x-ray except the x-ray tube and the bucky are connected and rotate on a pivoting point called a fulcrum. The x-ray tube goes through more wear and tear due to the fact that the x-ray stays on for the entire exposure which can last several seconds.This is the linear tomography machine that is located at clara mass you can see the connection between the x-ray tube and the image receptor


Linear tomograph is mainly used for certain anatomy that absorb x-rays in the same manner like the abdomen and the skull. Linear Tomography is mostly used in IVP to eliminate any organs that are obstructing the kidneys, but linear tomography can also be used for other areas like the skull to focus on the small bones of the ear the temperal bone has to be removed.This is a picture of a dacryocystography they are looking at the lacramal sacs in the nasal area, .
This an IVP you can see the contrast that is in the ureters and bladder and the kidney shadows with no obstruction.